Patent attributes
A method and apparatus are provided for the differential diagnosis of a patient with progressive supranuclear palsy (PSP) from a patient with Parkinson's disease (PD). One method includes identifying a plurality of partially repetitive eye movements that over time define square wave jerks, each square wave jerk of the plurality of square wave jerks defined by a first horizontal saccadic movement that moves the eye away from a fixation target followed by a corrective saccadic movement towards the target shortly thereafter, measuring a vertical component associated with the plurality of square wave jerks, comparing the vertical component with a threshold value. PSP or PD is identified by comparison of the vertical component with the threshold value. In another embodiment, a patient's saccade rate is determined and compared to a threshold value, and PSP or PD is identified based upon the comparison of the saccade rate with the threshold value.
